Overview of seizure disorder

Revised operational classification of seizure types and epilepsies by the International League Against Epilepsy (ILAE)

What’s new?

The classification has been revised. Seizures are divided into those of focal, generalized, unknown onset, with subcategories of motor, non-motor, with retained or impaired awareness for focal seizures.

Introduction

A seizure is defined as "a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain".
[1]Fisher RS, Acevedo C, Arzimanoglou A, et al. ILAE official report: a practical clinical definition of epilepsy. Epilepsia. 2014;55:475-482.
http://www.ncbi.nlm.nih.gov/pubmed/24730690?tool=bestpractice.com
Epilepsy is considered to be a disease of the brain defined by any of the following conditions:
[1]Fisher RS, Acevedo C, Arzimanoglou A, et al. ILAE official report: a practical clinical definition of epilepsy. Epilepsia. 2014;55:475-482.
http://www.ncbi.nlm.nih.gov/pubmed/24730690?tool=bestpractice.com
ILAE: EpilepsyDiagnosis.org

One unprovoked (or reflex) seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after 2 unprovoked seizures, occurring over the next 10 years

Diagnosis of an epilepsy syndrome.

Epileptic seizures may be classified as focal, generalized, or unknown onset, with subcategories of motor, non-motor (absence), with retained or impaired awareness for focal seizures.
[2]Fisher RS, Cross JH, French JA, et al. Operational classification of seizure types by the International League Against Epilepsy: position paper of the ILAE Commission for Classification and Terminology. Epilepsia. 2017;58:522-530.
http://onlinelibrary.wiley.com/doi/10.1111/epi.13670/full
http://www.ncbi.nlm.nih.gov/pubmed/28276060?tool=bestpractice.com
[3]Scheffer IE, Berkovic S, Capovilla G, et al. ILAE classification of the epilepsies: position paper of the ILAE Commission for Classification and Terminology. Epilepsia. 2017;58:512-521.
http://onlinelibrary.wiley.com/wol1/doi/10.1111/epi.13709/full
http://www.ncbi.nlm.nih.gov/pubmed/28276062?tool=bestpractice.com

Focal (partial) seizures are the electrical and clinical manifestations of seizures that arise from one portion of the brain. The EEG will indicate a local discharge over the area of onset. The temporal lobe is the most common area of onset for focal seizures, but they may arise from any lobe. Consciousness may be preserved in focal seizures (focal aware seizure) or may include memory loss for the duration of the clinical event or loss of consciousness (focal impaired awareness seizure). Focal seizures may lead to secondary generalized seizures. Monotherapy with antiepileptic medication is the preferred initial treatment.

An epilepsy syndrome typically presenting in infancy, with a varying etiology. EEG demonstrates hypsarrhythmia as a characteristic pattern, although it is not universally present at all times. Treatment options include hormonal therapy (ACTH or corticosteroids) or vigabatrin.
[15]Go CY, Mackay MT, Weiss SK, et al. Evidence-based guideline update: medical treatment of infantile spasms. Report of the Guideline Development Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society. Neurology. 2012;78:1974-1980.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3369510/
http://www.ncbi.nlm.nih.gov/pubmed/22689735?tool=bestpractice.com

Differentiating between syncope and epileptic seizures can sometimes be challenging. Twitching and jerking are often seen with vasovagal or cardiac syncope, which can be differentiated from rhythmic jerking of all the limbs in tonic-clonic seizures. Loss of bowel and bladder control, commonly seen with seizures, is rare during syncope. Postictal confusion is one of the key differentiating factors for seizures.
[16]Huff JS, Decker WW, Quinn JV, et al. Clinical policy: critical issues in the evaluation and management of adult patients presenting to the emergency department with syncope. Ann Emerg Med. 2007;49:431-444.
http://www.ncbi.nlm.nih.gov/pubmed/17371707?tool=bestpractice.com